What is the recommended insulin treatment regimen for patients with diabetes in a non-Intensive Care Unit (ICU) setting?

Insulin Treatment in Non-ICU Settings

For non-critically ill hospitalized patients with diabetes, use a scheduled basal-bolus insulin regimen (basal insulin once daily plus rapid-acting insulin before meals) rather than sliding scale insulin alone, targeting premeal glucose <140 mg/dL and random glucose <180 mg/dL. 1

Recommended Insulin Regimens by Clinical Scenario

Patients with Good Oral Intake (Eating Regular Meals)

Use a basal-bolus regimen with three components: [1, 1

• Basal insulin: Glargine or detemir once daily (typically at bedtime) to suppress hepatic glucose production 1
• Prandial (nutritional) insulin: Rapid-acting insulin analog (aspart, lispro, or glulisine) before each meal to cover carbohydrate intake 1
• Correction insulin: Additional rapid-acting insulin before meals and at bedtime for glucose >140 mg/dL 1

Starting dose calculation: Begin with 0.4-0.5 units/kg/day total daily dose, divided as 50% basal and 50% prandial (split equally among three meals) [1, 1

Patients with Poor Oral Intake or NPO Status

Use basal insulin plus correction doses only: [1, 1

• Administer basal insulin (glargine or detemir) once daily 1
• Add rapid-acting insulin correction doses every 4-6 hours for glucose >140 mg/dL 1
• Do not give scheduled prandial insulin if the patient is not eating consistently 1

Starting dose for insulin-naive patients: 0.1-0.2 units/kg once daily, or a flat dose of 10 units once daily 2

Elderly or Frail Patients

Use more conservative targets and lower starting doses: 1

• Target premeal glucose <140 mg/dL and random <180 mg/dL, but individualize based on hypoglycemia risk 1
• Start with reduced total daily dose of 0.1-0.15 units/kg/day, given mainly as basal insulin 1
• Consider less aggressive correction insulin thresholds (start corrections at glucose >180-200 mg/dL rather than >140 mg/dL) 3

Blood Glucose Targets

Standard targets for most non-ICU patients: [1, 1

• Premeal glucose: <140 mg/dL (7.8 mmol/L) 1
• Random glucose: <180 mg/dL (10.0 mmol/L) 1
• Reassess regimen if glucose falls below 100 mg/dL (5.6 mmol/L) to prevent hypoglycemia 1
• Modify regimen immediately if glucose <70 mg/dL (3.9 mmol/L) unless easily explained by missed meal 1

Monitoring Requirements

Bedside glucose monitoring frequency: 1

• Patients eating meals: Before each meal and at bedtime (4 times daily) 1
• Patients NPO or on continuous feeds: Every 4-6 hours 1

Critical Pitfalls to Avoid

Never Use Sliding Scale Insulin Alone

Sliding scale insulin (SSI) as the sole regimen is strongly discouraged and potentially dangerous: [1, 1, 4

• SSI treats hyperglycemia reactively after it occurs rather than preventing it 5
• Results in undesirable glycemic fluctuations and increased hospital complications 4
• Associated with poorer outcomes compared to scheduled basal-bolus regimens 5

Avoid Oral Antidiabetic Agents in Most Hospitalized Patients

Insulin is the preferred agent for managing hyperglycemia in the hospital: [1, 1

• Oral agents are difficult to titrate rapidly and have delayed onset of action 5
• Metformin carries risk of lactic acidosis in unstable patients 1
• SGLT2 inhibitors should be discontinued 3-4 days before surgery and avoided during hospitalization due to DKA risk 4

Correction Insulin Threshold Considerations

Recent evidence suggests less aggressive correction thresholds may be appropriate: 3

• A 2022 randomized trial found that correcting glucose only when >260 mg/dL (rather than >140 mg/dL) resulted in equivalent glycemic control with less insulin administration in patients already on optimal basal-bolus regimens 3
• This approach reduced the proportion of patients requiring correction insulin from 91% to 34% without worsening glucose control 3
• However, this applies only to patients already receiving adequate scheduled basal and prandial insulin 3

Transitioning from IV to Subcutaneous Insulin

When moving stable patients from ICU to floor: 4

• Calculate total daily subcutaneous dose as 60-80% of the IV insulin infusion rate during the prior 6-8 hours when glucose was stable 4
• Administer subcutaneous basal insulin 2 hours before discontinuing IV insulin to prevent rebound hyperglycemia 4
• Divide total daily dose as 50% basal and 50% prandial (split among three meals) 4

Alternative Regimen: Basal Plus Correction

The "Basal Plus" regimen is an acceptable alternative to full basal-bolus: [6, 7

• Consists of once-daily basal insulin plus correction doses of rapid-acting insulin before meals only when glucose >140 mg/dL 6
• Results in similar glycemic control to basal-bolus regimen with potentially less complexity [6, 7
• May be particularly useful in surgery patients or those with unpredictable oral intake 7
• This differs from sliding scale insulin alone because it includes scheduled basal insulin 6